scholarly journals Doppler-Based Algorithm for Mapping Cardiac Rotors by Induced Temperature Perturbations

2018 ◽  
Author(s):  
Guy Malki ◽  
Ofer Barnea ◽  
Tamir Tuller
Keyword(s):  
Dominant Frequency ◽  
Temperature Perturbation ◽  
Success Rates ◽  
New Approach ◽  
Mathematical Algorithm ◽  
Doppler Shifts ◽  
Initial Location ◽  
Origin Region ◽  
Array Position ◽  
Drift Trajectory

AbstractElectrogram-guided ablation for mapping of abnormal atrial activity has become increasingly popular in clinical applications. However, current methods have several limitations, and none have been shown to increase the ablation procedure success rate more than empirical ablation procedures. Here we present a new approach to identify arrhythmogenic sources as targets for ablation. Based on our previous findings that rotor drifting can be characterized by a local temperature gradient within the tissue, this article describes an innovative induced temperature technique which exploits the fact that rotor drifting produces Doppler shifts in the dominant frequency as measured at stationary locations. A mathematical algorithm is detailed to solve the inverse problem, reconstruct the drift trajectory, and predict the rotor origin location. Mathematical modeling and computer simulations demonstrate the feasibility of the new approach for rotors and focal source, two well-known arrhythmogenic sources of irregular conduction. Performance was extensively investigated for different numbers of electrodes and varied SNRs. Random conditions were also taken into account, since the electrodes’ array position and the initial location of the rotor pivot can impact the outcomes. By using temperature perturbation and employing the Doppler algorithm, the rotor drift trajectory and the origin region is shown to be estimated. We consider ways in which this technique can be extended to differentiate between rotors and ectopic activity. Future experimental and clinical validations should lead to potential use in ablation procedures and improve localization capabilities, thus increasing success rates and optimizing arrhythmia management.

Impact of a New Teaching and Learning Approach in an Introductory Programming Course

2017 ◽  
Vol 55 (6) ◽  
pp. 789-819 ◽  
Author(s):  
Sohail Iqbal Malik ◽  
Jo Coldwell-Neilson
Keyword(s):  
Teaching And Learning ◽  
Positive Impact ◽  
Dropout Rates ◽  
Success Rates ◽  
Final Exam ◽  
Introductory Programming ◽  
New Approach ◽  
Course Materials ◽  
Didactic Triangle ◽  
The Impact

High failure and dropout rates are reported in introductory programming (IP) courses in different studies despite extensive research attempting to address the issue. In this study, we introduced an ADRI (Approach, Deployment, Result, Improvement) approach in the teaching and learning process of an IP course to improve learning and success rates. All three entities of the didactic triangle (student, instructor, and content) were involved in the research to better understand and execute the proposed approach. The IP course materials were redesigned based on the ADRI approach, and an editor was developed to promote the new approach and encourage students to complete the various stages required in the approach. Two surveys were conducted, and final exam grades over four semesters were compared with determine the impact of including the ADRI approach in the course. We concluded that the ADRI approach provides a positive impact on outcomes that the students achieved during the course. It engages students in practicing their programming skills and provides a new presentation style for examples and exercises which discourages students from taking programming shortcuts. It not only helps to reduce the failure and, significantly, the dropout rates from the IP course but also impacts positively on all students who passed the IP course.

scholarly journals Methodology for Optimal Placement of Containers in Trains in Case of Cargo Operations Along the Route

2021 ◽  
Vol 19 (1) ◽  
pp. 174-193
Author(s):  
D. I. Kochneva ◽  
S. V. Siziy ◽  
Hao Chang
Keyword(s):  
Container Terminal ◽  
Container Terminals ◽  
Optimal Placement ◽  
Intermediate Point ◽  
Iterative Search ◽  
New Approach ◽  
Cargo Handling ◽  
Mathematical Algorithm ◽  
Passenger Traffic ◽  
Optimisation Methods

A new approach to organisation of container block trains is considered based on the principles of passenger traffic. The technology assumes container train’s traffic subject to the timetable with sale of cargo space in the train. The train is made up at the departure station and follows the established route with stops at intermediate container terminals or stations, where a container for which this station is designated as destination is removed and a new container is placed on the vacated place to be delivered to subsequent points of the route.The objective of this study is to develop a methodology for optimal placement of containers in a block train intended for en route cargo handling operations. The technique involves an iterative search for such an order of placement of packages so that containers assigned to each intermediate point are as close to each other as possible. The technique is an authors’ algorithm based on combinatorial optimisation methods.The implementation of the proposed algorithm makes it possible to reduce the excessive mileage of handlers and loaders at intermediate points and, consequently, to increase speed of cargo operations when rearranging containers, as well as to reduce operating costs of using the loading facilities of the container terminal.The proposed mathematical algorithm as compared to exhaustive search allows significantly reducing the number of iterations in search for a solution and can be implemented as software.

scholarly journals A New Approach for the Analysis of Deep Convective Events: Thunderstorm Intensity Index

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 908
Author(s):  
Damjan Jelić ◽  
Maja Telišman Prtenjak ◽  
Barbara Malečić ◽  
Andreina Belušić Vozila ◽  
Otília Anna Megyeri ◽  
...  
Keyword(s):  
Wind Speed ◽  
Temporal Resolution ◽  
Small Area ◽  
Data Sources ◽  
Mountain Regions ◽  
New Approach ◽  
Mathematical Algorithm ◽  
Intensity Index ◽  
Radar Imagery ◽  
Instability Indices

In this study, an investigation of a new thunderstorm intensity index (TSII) derived from lightning data is performed, along with its relationship to rain, wind, hail and waterspouts as well as instability indices (CAPE, LI, KI, and DLS). The study area is located in the northeastern Adriatic and includes various terrain types in a relatively small area (coastal, flatlands, hills and valleys, and mountain regions). The investigated period covers 11 years (2008–2018). The mathematical algorithm standing behind the TSII is based on the well-established methodology of lightning jump, allowing us to recognize areas where intensification in thunderstorms occurred. Our results suggest that these areas (with a positive TSII) experience significantly higher rain intensities and have higher total amounts of precipitation compared with areas where thunderstorms did not generate a TSII. Moreover, 76% of thunderstorm hail cases were associated with the presence of a TSII within a 15 km distance. The maximum reported wind speed also has higher values on a day with a TSII. Out of 27 waterspout events associated with lightning, 77% were related to a TSII. Due to the good spatial (3 km × 3 km) and high temporal (2 min) resolution of lightning data, the TSII can recognize even a local and short-lived intense system that is often misread by radars and satellites due to their inferior temporal resolution. The TSII is designed to be used as a climatological and diagnostic variable that could serve in lieu of more established data sources (e.g., station measurements and observations, radar imagery, etc.) if they are unavailable.

scholarly journals Patterned Illumination Techniques in Optogenetics: An Insight Into Decelerating Murine Hearts

2022 ◽  
Vol 12 ◽  
Author(s):  
Laura Diaz-Maue ◽  
Janna Steinebach ◽  
Claudia Richter
Keyword(s):  
Ex Vivo ◽  
Global Illumination ◽  
Heart Rhythm ◽  
Success Rates ◽  
New Approach ◽  
Life Saving ◽  
Cardiac System ◽  
Patterned Illumination ◽  
Insight Into

Much has been reported about optogenetic based cardiac arrhythmia treatment and the corresponding characterization of photostimulation parameters, but still, our capacity to interact with the underlying spatiotemporal excitation patterns relies mainly on electrical and/or pharmacological approaches. However, these well-established treatments have always been an object of somehow heated discussions. Though being acutely life-saving, they often come with potential side-effects leading to a decreased functionality of the complex cardiac system. Recent optogenetic studies showed the feasibility of the usage of photostimulation as a defibrillation method with comparatively high success rates. Although, these studies mainly concentrated on the description as well as on the comparison of single photodefibrillation approaches, such as locally focused light application and global illumination, less effort was spent on the description of excitation patterns during actual photostimulation. In this study, the authors implemented a multi-site photodefibrillation technique in combination with Multi-Lead electrocardiograms (ECGs). The technical connection of real-time heart rhythm measurements and the arrhythmia counteracting light control provides a further step toward automated arrhythmia classification, which can lead to adaptive photodefibrillation methods. In order to show the power effectiveness of the new approach, transgenic murine hearts expressing channelrhodopsin-2 ex vivo were investigated using circumferential micro-LED and ECG arrays. Thus, combining the best of two methods by giving the possibility to illuminate either locally or globally with differing pulse parameters. The optical technique presented here addresses a number of challenges of technical cardiac optogenetics and is discussed in the context of arrhythmic development during photostimulation.

scholarly journals Conventional Industrial Robotics Applied to the Process of Tomato Grafting Using the Splicing Technique

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 880 ◽  
Author(s):  
José-Luis Pardo-Alonso ◽  
Ángel Carreño-Ortega ◽  
Carolina-Clara Martínez-Gaitán ◽  
Iacopo Golasi ◽  
Marta Gómez Galán
Keyword(s):  
Low Cost ◽  
Industrial Robots ◽  
Success Rates ◽  
Skilled Workers ◽  
New Approach ◽  
Industrial Robotics ◽  
Temperature Conditions ◽  
High Degree

Horticultural grafting is routinely performed manually, demanding a high degree of concentration and requiring operators to withstand extreme humidity and temperature conditions. This article presents the results derived from adapting the splicing technique for tomato grafting, characterized by the coordinated work of two conventional anthropomorphic industrial robots with the support of low-cost passive auxiliary units for the transportation, handling, and conditioning of the seedlings. This work provides a new approach to improve the efficiency of tomato grafting. Six test rates were analyzed, which allowed the system to be evaluated across 900 grafted units, with gradual increases in the speed of robots work, operating from 80 grafts/hour to over 300 grafts/hour. The results obtained show that a higher number of grafts per hour than the number manually performed by skilled workers could be reached easily, with success rates of approximately 90% for working speeds around 210–240 grafts/hour.

scholarly journals Postal Envelope Segmentation using Learning-Based Approach

2008 ◽  
Vol 11 (2) ◽  
Author(s):  
Horacio A Legal-Ayala ◽  
Jacques Facon ◽  
Benjamín Barán
Keyword(s):  
Nearest Neighbor ◽  
Input Image ◽  
Success Rates ◽  
K Nearest Neighbor ◽  
Postal Address ◽  
New Approach ◽  
Complex Envelope ◽  
Accuracy Measure ◽  
And Performance ◽  
The Moment

This paper presents a learning-based approach to segment postal address blocks where the learning step uses only one pair of images (a sample image and its ideal segmented solution). First, this approach learns the available knowledge among pixels (each gray level) in an input image and its corresponding output in the ideal segmented solution. A classification array is generated which is re-utilized during the segmentation of new images. Features are extracted and updated by means of an adaptive square neighborhood. At the moment of new image segmentation, the submitted images are segmented by means of a k-Nearest Neighbor (k-NN) algorithm that seeks, for each pixel, the best solution in the classification array. Tests on a database of 200 complex envelope images were performed and a pixel to pixel accuracy measure validates the new approach. Results compared to other approaches for the same database show the efficiency and performance of the proposed learning-based approach. Success rates achieved for address block, stamps, rubber stamps and noise suggest that the features used in the proposed approach improves the segmentation results.

scholarly journals The concept of automatic generation of hydraulic press cycle

2021 ◽  
Author(s):  
Denis Jankovič ◽  
Rok Novak ◽  
Marko Šimic ◽  
Niko Herakovič
Keyword(s):  
Tracking System ◽  
High Volume ◽  
Automatic Generation ◽  
Hydraulic Press ◽  
Production Plan ◽  
New Approach ◽  
Mathematical Algorithm ◽  
Bending Process ◽  
Characteristic Points ◽  
Press Cycle

The development of smart hydraulic press that allows rapid adaptation to high-volume variant production is a major challenge. Besides tool management, setting the control parameters, which can be considered as a correct press cycle, is an important part to achieve agile production. This paper presents a new approach to automatically generate a hydraulic press cycle where the important data of the production plan is known, such as the data or setting of the forming tool and the data of the product. In this case, RFID tracking system is used to read the tool/product data, which is input data for the mathematical algorithm for calculating the characteristic points of the hydraulic press cycle. The characteristic points are sent to the local PLC and stored as a matrix. The Beckhoff TwinCat platform is used for process control. Finally, a simple bending process is shown as a use case for concept verification.

scholarly journals Landmark-free geometric methods in biological shape analysis

2015 ◽  
Vol 12 (113) ◽  
pp. 20150795 ◽  
Author(s):  
Patrice Koehl ◽  
Joel Hass
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Deformation Energy ◽  
Conformal Map ◽  
Success Rates ◽  
Genus Zero ◽  
Evolutionary Patterns ◽  
New Approach ◽  
Discrete Conformal Map ◽  
Biological Shape

In this paper, we propose a new approach for computing a distance between two shapes embedded in three-dimensional space. We take as input a pair of triangulated genus zero surfaces that are topologically equivalent to spheres with no holes or handles, and construct a discrete conformal map f between the surfaces. The conformal map is chosen to minimize a symmetric deformation energy E sd ( f ) which we introduce. This measures the distance of f from an isometry, i.e. a non-distorting correspondence. We show that the energy of the minimizing map gives a well-behaved metric on the space of genus zero surfaces. In contrast to most methods in this field, our approach does not rely on any assignment of landmarks on the two surfaces. We illustrate applications of our approach to geometric morphometrics using three datasets representing the bones and teeth of primates. Experiments on these datasets show that our approach performs remarkably well both in shape recognition and in identifying evolutionary patterns, with success rates similar to, and in some cases better than, those obtained by expert observers.

Seismic resolution enhancement using scale transform in the time-frequency domain

Geophysics ◽  
2018 ◽  
Vol 83 (6) ◽  
pp. V305-V314 ◽  
Author(s):  
Niloofar Alaei ◽  
Amin Roshandel Kahoo ◽  
Abolghasem Kamkar Rouhani ◽  
Mehrdad Soleimani
Keyword(s):  
Frequency Domain ◽  
Resolution Enhancement ◽  
Dominant Frequency ◽  
Thin Layers ◽  
Scale Transformation ◽  
Data Sets ◽  
Petroleum Reservoir ◽  
New Approach ◽  
Time Frequency ◽  
Magnitude Spectrum

Reducing uncertainty in geologic interpretation of petroleum reservoir containing thin layers requires increasing vertical resolution via appropriate advanced resolution enhancement methods. This problem was resolved here by introducing an alternative approach in resolution enhancement. Our method uses Gabor deconvolution (GD) combined with wavelet scaling. First, the seismic trace is transformed in the time-frequency domain using the Gabor transform. Subsequently, the Gabor magnitude spectrum of the seismic trace is smoothed to estimate the wavelet magnitude, which is then divided by the original value on the Gabor magnitude spectrum along the frequency axis to design a scale transformation filter. Finally, the filtered Gabor magnitude spectrum of the seismic trace is transformed back to the time domain using an inverse Gabor transformation. The result of using this technique is an increase of the dominant frequency, which produces a higher resolution of the seismic trace compared with using only the original GD. This method was applied to two synthetic and one field seismic data sets and compared with using only a GD. After applying the new approach, all three data sets indicate an extension in bandwidth (BW) and an enhancement in the resolution adequate for thin-layer seismic interpretation. When compared with the data sets using only a GD, the new approach produced comparable extension in the effective BW, while it pushing the dominant frequency to higher values. This allowed the imaging of many thin layers and geologic intervals in the field data example that could not be interpreted by the GD method.

scholarly journals Artificial Diets Modulate Infection Rates by Nosema ceranae in Bumblebees

2021 ◽  
Vol 9 (1) ◽  
pp. 158
Author(s):  
Tamara Gómez-Moracho ◽  
Tristan Durand ◽  
Cristian Pasquaretta ◽  
Philipp Heeb ◽  
Mathieu Lihoreau
Keyword(s):  
Bombus Terrestris ◽  
Parasite Prevalence ◽  
Nosema Ceranae ◽  
Success Rates ◽  
Artificial Diets ◽  
Experimental Conditions ◽  
New Approach ◽  
Low Protein ◽  
Energetic Stress ◽  
Colony Collapse

Parasites alter the physiology and behaviour of their hosts. In domestic honey bees, the microsporidia Nosema ceranae induces energetic stress that impairs the behaviour of foragers, potentially leading to colony collapse. Whether this parasite similarly affects wild pollinators is little understood because of the low success rates of experimental infection protocols. Here, we present a new approach for infecting bumblebees (Bombus terrestris) with controlled amounts of N. ceranae by briefly exposing individual bumblebees to parasite spores before feeding them with artificial diets. We validated our protocol by testing the effect of two spore dosages and two diets varying in their protein to carbohydrate ratio on the prevalence of the parasite (proportion of PCR-positive bumblebees), the intensity of parasites (spore count in the gut and the faeces), and the survival of bumblebees. Overall, insects fed a low-protein, high-carbohydrate diet showed the highest parasite prevalence (up to 70%) but lived the longest, suggesting that immunity and survival are maximised at different protein to carbohydrate ratios. Spore dosage did not affect parasite infection rate and host survival. The identification of experimental conditions for successfully infecting bumblebees with N. ceranae in the lab will facilitate future investigations of the sub-lethal effects of this parasite on the behaviour and cognition of wild pollinators.

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